Instantly share code, notes, and snippets.

Embed
What would you like to do?
#include <sys/uio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <sys/socket.h>
#include <time.h>
#include <stdlib.h>
int read_cross(pid_t pid, char *mybuf, char *theirbuf, size_t length) {
struct iovec local[1];
struct iovec remote[1];
local[0].iov_base = mybuf;
local[0].iov_len = length;
remote[0].iov_base = theirbuf;
remote[0].iov_len = length;
return process_vm_readv(pid, local, 1, remote, 1, 0);
}
typedef struct {
pid_t pid;
} shake_hand_t;
typedef struct {
int length;
char *buf;
char free;
} data_t;
void loop(int fd, int pid) {
data_t data;
read(fd, &data, sizeof(data));
if (data.free) {
free(data.buf);
} else {
char *buf = malloc(data.length);
int nread = read_cross(pid, buf, data.buf, data.length);
//printf("nread: %d error: %s tpid:%d pid:%d content: %s buf:%x data.buf: %x\n", nread, strerror(errno), pid, getpid(), buf, buf, data.buf);
//sprintf(buf, "%d", atoi(buf) + 1);
//sleep(1);
data.free = 1;
write(fd, &data, sizeof(data));
data.free = 0;
data.buf = buf;
write(fd, &data, sizeof(data));
}
}
int main(int argc, char *argv[])
{
if (argc != 3) {
printf("usage: vm <message-size> <roundtrip-count>\n");
return 1;
}
int64_t size = atoi(argv[1]);
int64_t count = atol(argv[2]);
int sv[2];
socketpair(AF_UNIX, SOCK_STREAM, 0, sv);
pid_t child_pid = fork();
shake_hand_t sh;
sh.pid = getpid();
if (child_pid) { // parent
close(sv[1]);
int fd = sv[0];
write(fd, &sh, sizeof(sh));
read(fd, &sh, sizeof(sh));
pid_t pid = sh.pid;
data_t data;
data.free = 0;
data.length = size;
data.buf = malloc(data.length);
sprintf(data.buf, "%d", 1);
write(fd, &data, sizeof(data));
struct timespec start, stop;
int64_t delta;
clock_gettime(CLOCK_MONOTONIC, &start);
int64_t idx = 0;
while(++idx < count) loop(fd, pid);
clock_gettime(CLOCK_MONOTONIC, &stop);
delta = ((stop.tv_sec - start.tv_sec) * 1000000000 +
(stop.tv_nsec - start.tv_nsec));
printf("average latency: %li ns\n", delta / (count * 2));
} else {
malloc(1234);
close(sv[0]);
int fd = sv[1];
write(fd, &sh, sizeof(sh));
read(fd, &sh, sizeof(sh));
pid_t pid = sh.pid;
while(1) loop(fd, pid);
}
return 0;
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment